Adhesion promoter

ABSTRACT

An adhesion promoter for a hot melt adhesive or a pressure sensitive adhesive prepared by admixing a hydrolytic silane compound with an aqueous buffer solution. The adhesive is able to bind at very low surface free energy substrates, such as Xerographic prints contaminated by silicone fuser oil. The hot melt adhesive maintains a substantially stable viscosity at temperature ranging from about 100° C. to about 200° C.

BACKGROUND

The present disclosure generally relates to adhesion promoterscomprising a hydrolytic silane compound admixed with an aqueous buffersolution, and their use in methods for promoting adhesion of adhesivesto a substrate. In embodiments, the adhesion promoter may be used in ahot melt adhesive or a pressure sensitive adhesive that is to be appliedto a substrate.

The addition of the adhesion promoter to hot melt adhesives or pressuresensitive adhesives improves adhesion to very low surface free energysubstrates. The admixed hydrolytic silane compound with aqueous buffersolution improves the thermal stability of the adhesive and theviscosity of the adhesive remains relatively constant at temperatures,for example, ranging from about 100° C. to about 200° C. The adhesivecontaining the admixed silane adhesion promoter is thus able to bindvery low surface free energy substrates such as Xerographic printscontaminated with fuser oil, and maintains a substantially stableviscosity at adhesive application or operating temperatures from about100° C. to 200° C.

REFERENCES

In a typical imaging device, a light image of an original to be copiedis recorded in the form of a latent image upon a photosensitive member,and the latent image is subsequently rendered visible by the applicationof resin particles and pigment particles, or toner. The visible tonerimage is then in a loose powdered form and can be easily disturbed ordestroyed. The toner image may be fixed or fused upon a support, whichmay be a support sheet such as plain paper, using a fuser roll.

To ensure and maintain good release properties of the fuser roll, it hasbecome customary to apply release agents to the fuser roll during thefusing operation. Typically, these materials are applied as thin filmsof, for example, nonfunctional silicone oils or mercapto- oramino-functional silicone oils, to prevent toner offset.

U.S. Pat. No. 4,029,827 discloses the use of polyorganosiloxanes havingmercapto functionality as release agents.

U.S. Pat. No. 4,101,686 and U.S. Pat. No. 4,185,140 disclose polymericrelease agents having functional groups such as carboxy, hydroxy, epoxy,amino, isocyanate, thioether, or mercapto groups.

U.S. Pat. No. 5,157,445 discloses toner release oil having a functionalorganopolysiloxane.

Fuser oil unavoidably contaminates the surface of prints duringXerographic printing process. Because the fuser oil is chemically boundon the paper surface during the hot fusing process, especially forexample with mercapto or amino functionalized fuser oil, it may bedifficult to wipe off the fuser oil, and the surface free energy of theXerographic prints is significantly lowered because of the oilcontamination and thus causes poor binding between the adhesive andprints.

The adhesion may be improved by adding amino or mercapto functionalhydrolytic silane compound or oligosiloxane silane to adhesives asadhesion promoters, but at the same time the silane may decrease the potlife of the adhesive. The viscosity may continuously increase during theapplication process at the application temperature such as from 100° C.to 200° C. The viscosity continuously increases and may cause operatingproblems.

In some extreme cases, such as Xerographic prints printed on the offsetpreprint forms, there is no commercial available adhesive that can beused to bind these kind of prints.

U.S. patent application Ser. No. 11/532,704, incorporated herein byreference in its entirety, describes an adhesion promoter comprising asilane compound and a release agent and/or adhesive.

While hot melt adhesives are known in the prior art, for example, U.S.Pat. No. 5,401,791 discloses bookbinding adhesives, U.S. Pat. No.4,772,650 discloses bookbinding adhesive composition for bookcasemaking, U.S. Pat. No. 4,712,808 discloses bookbinding adhesivecomposition for hinge joint, U.S. Pat. No. 4,660,858 disclosesbookbinding adhesive composition for book lining, U.S. Pat. No.4,140,733 discloses polyethylene based bookbinding hot melt adhesives,they are all unsatisfactory in adhesive strength for perfect bookbinding applications when they are used for binding xerographicprints/paper substrates contaminated by fuser oils.

U.S. Pat. No. 6,800,680, U.S. Pat. No. 6,797,774, U.S. Pat. No.6,794,443, U.S. Pat. No. 6,582,829, U.S. Pat. No. 5,518,571, U.S. Pat.No. 5,057,561 and U.S. Pat. No. 4,942,195, disclose varies kinds ofpolymers for hot melt adhesive application.

U.S. Pat. No. 6,989,413, U.S. Pat. No. 6,833,404, U.S. Pat. No.5,021,499, U.S. Pat. No. 4,618,640 and U.S. Pat. No. 4,197,380 disclosetackifying resins for hot melt adhesive application.

U.S. Pat. No. 6,890,982, U.S. Pat. No. 6,060,550, U.S. Pat. No.5,063,271 and U.S. Pat. No. 5,037,874 disclose waxes for hot meltadhesive application.

U.S. Pat. No. 4,576,985 and U.S. Pat. No. 4,197,380 disclose hot meltadhesives for low surface energy substrates.

SUMMARY

While known compositions and processes may be suitable for theirintended purposes, and in fact materials of such known compositions canbe used herein as appropriate, a need remains for improved adhesionpromoters and adhesives containing adhesion promoters.

These and other improvements are accomplished by the adhesion promotersand adhesives described herein.

In embodiments, described is an adhesion promoter for hot melt adhesivesand pressure sensitive adhesives, comprising a silane composition formedby admixing a hydrolytic silane compound with an aqueous buffersolution.

In embodiments, described is a hot melt adhesive or pressure sensitiveadhesive including at least one adhesive promoter comprising a silanecomposition formed by admixing a hydrolytic silane compound with anaqueous buffer solution.

EMBODIMENTS

As explained above, it is known to apply release agents to the fuserroll to provide the necessary release of a substrate containing an imagethereon from the fuser roll after the toner image has been formed on thesubstrate. Release agents are known to those of ordinary skill in theart, and include release agents such as disclosed in U.S. PublicationNo. 2006/0008727, U.S. Publication No. 2004/0185272 and U.S. PublicationNo. 2003/0108737, each of which is incorporated herein by reference inits entirety. As used herein, “substrate” refers to any media that maybe printed on, such as paper, including synthetic paper, pre-printforms, plastic films, transparency, cardboard, cloth, etc.

Xerographic prints may be contaminated by a release agent such assilicone fuser oil due to the printing process. Some release agent mayremain on a toner image that may cover any portion of the substrate andon the substrate itself. In other words, some release agent may remainon a final substrate having an image thereon and may at least partiallycover a substrate having no toner image or a substrate having a tonerimage thereon. “Partially” refers to the release agent covering fromabove 0 percent to less than 100 percent of the substrate, such as fromabout 10 percent to about 90 percent or from about 20 percent to about80 percent of the substrate. The release agent may chemically bond tothe surface of the prints because of the reactive functional group suchas amino or mercapto functional group in fuser oil during fusing processat high pressure and high temperature. The surface free energy (SFE) ofthe prints may thus dramatically drop from a range of higher than about30 mN/m² for typical substrates such as paper to a range of from about 8mN/m² to less than about 30 mN/M². Generally, commercially available hotmelt adhesives bind to substrates having a SFE higher than about 30mN/m².

Any release agent remaining on the substrate, with or without a tonerimage thereon, may be detrimental to an adhesive attempting to adhere tothe substrate having a toner image. This is particularly important whenthe substrate is to be laminated or coated with a hot melt adhesive,such as an adhesive used in bookbinding. This release agent may alsoprevent materials utilizing adhesives, for example, POST-IT® notes, fromadhering to the substrate.

Typical release agents used in releasing a substrate from a fuser rollin an imaging device include poly-ogranofunctional siloxanes, such asamino-functional silicone oils, such as methyl aminopropyl methylsiloxane, ethyl aminopropyl methyl siloxane, benzyl aminopropyl methylsiloxane, dodecyl aminopropyl methyl siloxane, aminopropyl methylsiloxane, and the like.

Disclosed herein is an adhesion promoter that promotes the adhesion ofan adhesive to a substrate with surface free energy lower than 30 mN/m².The substrate may be at least partially covered by a release agent. Theadhesion promoter may also promote adhesion of an adhesive to asubstrate having no toner image or a substrate having a toner imagewithout being covered by a release agent.

It is desirable to have an adhesive with a stable viscosity that ismaintained constant during the application process. For example, theadhesive desirably has a stable viscosity at the applicationtemperature, such as a temperature from about 100° C. to 200° C., suchas from about 140° C. to about 190° C. or from about 150° C. to about180° C.

An adhesive that incorporates a conventional adhesion promoter mayencounter issues associated with the pot life of the adhesive. That is,the adhesive may not be able to be kept long enough in a hot pot to meetthe requirements during the application process, for example inbookbinding applications. The viscosity of the adhesive containing aconventional adhesion promoter may continuously increase and causeoperating problems.

It is thus desirable to have an adhesion promoter that can be added to ahot melt adhesive or pressure sensitive adhesive and at the same timemaintain the thermal stability of the adhesive, or maintain a longenough pot life and constant viscosity of the adhesive during theapplication process.

A thermally stable adhesive is one that substantially maintains itsviscosity and adhesion properties over a period of time. A stableviscosity, for example, is an increase or decrease in viscosity within1000 cp over the aging process at the application temperature, such asfrom about 100 to about 800 cp over 8 hours at an applicationtemperature or from about 200 to about 600 cp over 8 hours at anapplication temperature.

In embodiments, described is an adhesion promoter that includes a silanecompound that is pretreated with an aqueous buffer water solution beforeintroduction into an adhesive.

In embodiments the adhesion promoter before treatment may be a silanecompound, for example, a silane compound such as an alkyloxysilanecompound or a glycidoxy silane compound. Further examples includeorganic silane compounds, which may comprise at least one silane grouprepresented by the following formula:

—Si(R)_(3-m)X_(m)

wherein R may be a C₁-C₃₀ hydrocarbyl including an alkyl, an aryl, avinyl and the like, wherein the hydrocarbyl may further contain ahalogen, nitrogen, oxygen or sulfur atom. Illustrative examples of R mayinclude methyl, ethyl, propyl, octyl, phenyl, methacryloxypropyl,aminopropyl, aminoethylaminopropyl, phenylaminopropyl, chloropropyl,mercaptopropyl, acryloxypropyl, 3-glycidoxypropyl, trifluoropropyl,heptadecafluorodecyl, and isocyanatopropyl group and the like. X mayrepresent a hydrolyzable functional group, a C₁-C₂₀ alkoxy group, ahydroxy group, a carboxylate group, an alkoxy group, an arylalkyloxygroup, and an aryloxy group, a halogen or a hydrogen atom, and m is aninteger of 1, 2 or 3.

In embodiments, R may be a non-hydrolyzable organic group, X may be ahydrolytic group and m may be an integer of 1, 2 or 3. X may include ahalide, a hydroxyl group, a carboxylate group, an alkoxyl group, anarylalkyloxy group and an aryloxy group. The hydrolytic silane compoundmay contain in total two of the hydrolytic X group.

In embodiments, the hydrolytic silane compound may include a functionalgroup. Examples of functional groups may include, for example, an aminogroup, a mercapto group, an epoxy group and a vinyl group.

Examples of silane compounds suitable for use herein includeaminoalkylsilane, mercaptoalkylsilane and mixtures thereof, for example,4-aminobutyltriethoxysilane, 1-amino-2-(dimethylethoxysilyl)propane,N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane,N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane,(aminoethylaminomethyl)phenethyltrimethoxysilane,N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane,N-(2-aminoethyl)-3-aminopropylsilanetriol,N-(2-aminoethyl)-3-aminopropyltriethoxysilane,N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,N-aminoethyl-AZA-2,2,4-trimethylsilacyclopentane,N-(6-aminohexyl)aminomethyl-trimethoxysilane,N-(6-aminohexyl)aminopropyl-trimethoxysilane,N-(2-aminoethyl)-11-aminoundecyl-trimethoxysilane,3-aminopropylmethylbis(trimethylsiloxy)silane,3-aminopropyldimethylethoxysilane, 3-aminopropyltrimethoxysilane,3-aminopropyltris(methoxyethoxyethoxy)silane,3-(triethoxysilyl)propylsuccinic anhydride,tris(3-trimethoxysilylpropyl)iso-cyanurate,(3-trimethoxysilylpropyl)diethylene-triamine, methyltrichlorosilane,dimethyldichlorosilane, methyltriethoxysilane, ethyltrichlorosilane,ethyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane,ethyltriethoxysilane, propyltrimethoxysilane, amino silanehydrochloride, 3-glycidoxypropyl trimethoxysilane (Z-6040, availablefrom Dow Corning; KBM 403, available from Shin-Etsu),methyltrimethoxysilane (Z-6070, available from Dow Corning; KBM 13,available from Shin-Etsu), methacryloxypropyltrimethoxysilane (Z-6030,available from Dow Coming; KBM502, available from Shin-Etsu),aminopropyltrimethoxysilane (Z-6011, available from Dow Coming; KBM903,available from Shin-Etsu), aminoethylaminopropyltrimethoxysilane(KBM603, available from Shin-Etsu or DOW Z 6032, available from DowCorning; KBM603, available from Shin-Etsu),trifluoropropyltrimethoxysilane (KBM7103, available from Shin-Etsu),heptadecafluorodecyltrimethoxysilane (KBM7803, available fromShin-Etsu), isocyanatopropyltriethoxysilane (KBE9007, available fromShin-Etsu), aminopropyltriethoxysilane (KBE903, available fromShin-Etsu), aminoethylaminopropyltriethoxysilane (KBE603, available fromShin-Etsu), alkyltrimethoxysilane (DOW HV 10, available from DowKorning), and a coating having trifluoropropy trimethoxysilane,vinylmethoxysilane, tetra(2-methoxyethoxy)silane (DOW 4040 Prime Coat,available from Dow Corning), mixtures thereof, and the like.

The adhesion promoter disclosed herein may include more than one silanecompound, for example, the adhesion promoter may include from about 1 toabout 5 silane compounds, such as from about 1 to about 3 silanes.

In embodiments, the silane compound is admixed with aqueous buffersolution before incorporation into an adhesive. The aqueous buffersolution may include a buffer agent. The aqueous buffer solution is madeby dissolving the buffer agent into distilled water. The buffer agentmay be an inorganic salt, for example an alkali metal phosphate, analkali metal sulfite and the like or an aqueous solution of an inorganicsalt. Other suitable buffer agents include aqueous solutions ofpotassium phosphate monobasic, potassium phosphate dibasic, sodiumhydrogen sulfite, mixtures thereof and the like, for example dissolvedin distilled water.

In embodiments, the aqueous buffer solution may be prepared to form fromabout 1% to about 50% by weight buffer solution, such as, from about 5%to about 25% by weight buffer solution, and for example from about 5% toabout 15% by weight buffer solution.

In embodiments, the pH of the buffer solution may be, for example, fromabout 2 to about 10, such as from about 4 to about 9.

In embodiments, the aqueous buffer solution may be added to the silanecompound, for example in a silane to buffer solution ratio from 1:0.005to 1:0.5, such as a ratio of 1:0.15 and for example a ratio of 1:0.35.The buffer solution may be added to the silane compound while agitatingthe silane compound at room temperature. The silane compound temperaturegoes up after the adding of the buffer solution because this may be anexothermic reaction process. The adhesion promoter may be kept agitatingfrom about 1 hour to about 3 hours before it is incorporated into hotmelt adhesives or pressure sensitive adhesives. The shelf life for theadmixed silane may be as long as three days or longer at roomtemperature.

The admixed silane adhesion promoter described herein provides at leasttwo beneficial functions in order to promote adhesion of the adhesive tothe substrate: (1) a reactive silicone group, that is, a group reactivewith silicone, for bonding with the Xerographic print or substrate, suchas a methoxy or an ethoxy group, and (2) an organic component forcompatibility with the adhesive.

The admixed adhesion promoter may be utilized in a variety of ways topromote the adhesion of an adhesive to a substrate. The admixed adhesionpromoter promotes adhesion to the substrate in locations where there isa toner image, where there is not toner image, and where there is atoner image at least partially covered by a release agent. In otherwords, the adhesion promoter promotes adhesion of an adhesive to asubstrate, regardless if the substrate has a toner image thereon, hasrelease agent thereon, or if the substrate has a toner image thereon,that is at least partially covered by a release agent.

In embodiments, the admixed adhesion promoter may be used as a separatecoating on the substrate to be used as a primer, dispersed within arelease agent, or incorporated into an adhesive.

In embodiments, the admixed adhesion promoter may be added directly tothe adhesive of the laminate or the bookbinding material, such as intopressure sensitive adhesive formulations or hot melt adhesiveformulations. The adhesive comprises a hot melt adhesive or pressuresensitive adhesive and an adhesion promoter pretreated with an aqueousbuffer solution.

Suitable hot melt adhesives for use herein include most commerciallyavailable hot melt adhesive, such as polyethylene, poly(ethylene/vinylacetate), polystyrene, polyamide, a polyolefin based polymer, polyester,phenol-formaldehyde resin, etc., of a homopolymer or a block copolymerbased hot melt adhesives. Other examples of commercially available hotmelt adhesives include for example HM220 available from Horizon andUS661 manufactured by U.S. Adhesives.

When the admixed silane compound used as an adhesion promoter is addedto a commercially available hot melt adhesive, the first step is to heatthe adhesive to the application temperature until the adhesive issubstantially melted or flows. Then the adhesion promoter is slowlyadded to the adhesive while keeping the application temperature and thespeed of the agitation controlled. The application temperature isdetermined by the adhesive formulation. The speed of the agitation maybe controlled from about 100 to about 500 rpm.

The adhesion promoter may be added to the adhesive formulation inamounts of from about 0.05 weight percent to about 5 weight percent ofthe adhesive formulation, such as from about 0.5 weight percent to about3 weight percent or from about 1 weight percent to about 2 weightpercent of the adhesive formulation.

By chemically bonding to both the adhesive and the substrate, thepretreated adhesion promoter promotes the adhesion of an adhesive to asubstrate having an oil contaminated surface with a Surface Free Energy(SFE) from less than about 30 mN/m², such as from about 8 mN/m²to lessthan about 30 mN/m², such as from about 10 mN/m² to about 28 mN/m² orfrom about 15 mN/m² to about 25 mN/m².

In embodiments, the adhesive may display a viscosity ranging for examplefrom about 1,000 centipose to about 20,000 centipose at temperaturesranging for example from about 120° C. to about 200° C.

Suitable hot melt adhesives formulation for use herein may includethermoplastics or materials which appear to be thermoplastic includingcomponents such as polymer resins, tackifiers, waxes, plasticizers,antioxidants and filler or combinations thereof

In embodiments, an optional plasticizer may be added to the commerciallyavailable hot melt adhesives or pressure sensitive adhesives. Theplasticizer may be added before or after the addition of an adhesionpromoter to the adhesive, but it is more desirable to add theplasticizer before the addition of the adhesion promoter to lower theinitial viscosity of the adhesive.

Examples of the optional plasticizer suitable for use herein mayinclude, for example, paraffinic linear oil, naphthenic cycloaliphaticoil, aromatic ring containing oil, white mineral oil commerciallyavailable as KAYDOL oil, polyisobutylene commercially available asINDOPOL H300, pentaerythritol tetrabenzoate commercially available asBENZOFLEX S552 (Velsicol Chemical Corporation), trimethyl titrate,commercially available as CITROFLEX 1 (Monflex Chemical Company),N,N-dimethyl oleamide, commercially available as HALCOMID M-18-OL (C. P.Hall Company), a benzyl phthalate, commercially available as SANTICIZER278 (Ferro Corporation), mixtures thereof and the like.

In embodiments, the optional plasticizer may be added to the adhesive,for example, in the amount of from about 1 to about 20% by weight, suchas from about 5 to about 15% by weight.

The most common general purpose hot melt adhesive is based on ethylenevinyl acetate (EVA) resins. Other polymers commonly used in hot meltadhesives and pressure sensitive adhesives include low densitypolyethylene, poly(ethylene/vinyl acetate), polyvinyl alcohol,polystyrene, polyamides, polyalkylene oxide, polyacrylate, ethyleneacrylic copolymers, polypropylene(atactic), phenoxy resins, polyesters,APAO, polyesteramides, polyurethanes, polyurethane prepolymers,thermalplastic acrylic polymers butyl rubbers, polyvinyl acetate andcopolymers, styrenic block copolymers (SIS, SBS, SEBS),phenol-formaldehyde resin of polymer or block copolymer, natural rubber,and a copolymer thereof etc.

Examples of suitable polymer resins that may be optionally used in thehot melt adhesives or pressure sensitive adhesives formulation or addedto the commercially available adhesives include poly(methylmethacrylate-butadiene), poly(ethyl methacrylate-butadiene), poly(propylmethacrylate-butadiene), poly(butyl methacrylate-butadiene), poly(methylacrylate-butadiene), poly(ethyl acrylate-butadiene), poly(propylacrylate-butadiene), poly(butyl acrylate-butadiene), poly(methylmethacrylate-isoprene), poly(ethyl methacrylate-isoprene), poly(propylmethacrylate-isoprene), poly(butyl methacrylate-isoprene), poly(methylacrylate-isoprene), poly(ethyl acrylate-isoprene), poly(propylacrylate-isoprene) and poly(butyl acrylate-isoprene),poly(styrene-butadiene), poly(methylstyrene-butadiene),poly(styrene-isoprene), poly(methylstyrene-isoprene),poly(styrene-propyl acrylate), poly(styrene-butyl acrylate),poly(styrene-butadiene-acrylic acid), poly(styrene-butadiene-methacrylicacid), poly(styrene-butadiene-acrylonitrile-acrylic acid),poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butylacrylate-methacrylic acid), poly(styrene-butylacrylate-acrylononitrile), and poly(styrene-butylacrylate-acrylononitrile-acrylic acid), block copolymer such asstyrene-isoprene-styrene (SIS) or styrene-butadiene-styrene (SBS),polyester or mixtures thereof and the like.

In embodiments, the polymer resin content in the hot melt adhesives orpressure sensitive adhesives may be in the amount of from about 20 toabout 50% by weight, such as from about 25 to about 35% by weight.

Examples of optional tackifiers used in hot melt adhesives and pressuresensitive adhesives include aliphatic and aromatic resins, hydrocarbonsand hydrogenated hydrocarbons or mixed C5/C9 resins, modified rosin,natural tackifiers are rosin acid derivatives and their esters, terpeneresins, pure monomers, hydrogenated pure monomers etc. and combinationsthereof. Examples of the optional tackifier suitable for use herein maybe Eastotac H100-W, Regalite S1100, Foralyn 110 from Eastman Chemical.

In embodiments, the optional tackifier may be added to the adhesive, forexample, in the amount of from about 5 to about 30% by weight.

Examples of the optional wax suitable for use herein may include naturaland synthetic waxes. Examples of natural waxes may include animal waxsuch as beeswax and lanolin wax, vegetable wax such as carnauba wax,mineral wax such as montan wax and paraffin wax, microcrystalline waxand slack wax. Examples of synthetic waxes suitable for used herein mayinclude polyethylene wax such as homopolymer wax and copolymer wax andmodified polymer wax, polypropylene wax such as homopolymer wax andmodified polymer wax, semicrystalline flexible polyolefins, paraffin waxand Fisher-Tropsch wax such as homopolymer wax and modified polymer wax.

In embodiments, the optional wax may be added to the adhesive, forexample, in the amount of from about 5 to about 20% by weight. Inembodiments, the wax may have a melting point for example from about 50°C. to about 150° C.

Examples of the optional antioxidant suitable for use herein includeprimary and secondary antioxidant or multifunctional antioxidant,hydroxylamines, N,N′-hexamethylene bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamamide) (IRGANOX 1098, available from Ciba-Geigy Corporation),2,2-bis(4-(2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy))ethoxyphenyl)propane(TOPANOL-205, available from ICI America Corporation),tris(4-tert-butyl-3-hydroxy-2,6-dimethyl benzyl)isocyanurate (CYANOX1790, 41,322-4, LTDP, Aldrich D12,840-6), 2,2′-ethylidenebis(4,6-di-tert-butylphenyl)fluoro phosphonite (ETHANOX-398, availablefrom Ethyl Corporation), tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenyldiphosphonite (ALDRICH 46,852-5; hardness value 90), pentaerythritoltetrastearate (TCI America #PO739), tributylammonium hypophosphite(Aldrich 42,009-3), 2,6-di-tert-butyl-4-methoxyphenol (Aldrich25,106-2), 2,4-di-tert-butyl-6-(4-methoxybenzyl)phenol (Aldrich23,008-1), 4-bromo-2,6-dimethylphenol (Aldrich 34,951-8),4-bromo-3,5-didimethylphenol (Aldrich B6,420-2), 4-bromo-2-nitrophenol(Aldrich 30,987-7), 4-(diethyl aminomethyl)-2,5-dimethylphenol (Aldrich14,668-4), 3-dimethylaminophenol (Aldrich D14,400-2),2-amino-4-tert-amylphenol (Aldrich 41,258-9),2,6-bis(hydroxymethyl)-p-cresol (Aldrich 22,752-8),2,2′-methylenediphenol (Aldrich B4,680-8),5-(diethylamino)-2-nitrosophenol (Aldrich 26,951-4),2,6-dichloro-4-fluorophenol (Aldrich 28,435-1), 2,6-dibromo fluorophenol (Aldrich 26,003-7), α-trifluoro-o-cresol (Aldrich 21,979-7),2-bromo-4-fluorophenol (Aldrich 30,246-5), 4-fluorophenol (AldrichF1,320-7), 4-chlorophenyl-2-chloro-1,1,2-tri-fluoroethyl sulfone(Aldrich 13,823-1), 3,4-difluoro phenylacetic acid (Aldrich 29,043-2),3-fluorophenylacetic acid (Aldrich 24,804-5), 3,5-difluoro phenylaceticacid (Aldrich 29,044-0), 2-fluorophenylacetic acid (Aldrich 20,894-9),2,5-bis(trifluoromethyl)benzoic acid (Aldrich 32,527-9),ethyl-2-(4-(4-(trifluoromethyl)phenoxy)phenoxy)propionate (Aldrich25,074-0), tetrakis (2,4-di-tert-butyl phenyl)-4,4′-biphenyldiphosphonite (Aldrich 46,852-5), 4-tert-amyl phenol (Aldrich 15,384-2),3-(2H-1-benzotriazol-2-yl)-4-hydroxy phenethylalcohol (Aldrich43,071-4), NAUGARD 76, NAUGARD 445, NAUGARD 512, AND NAUGARD 524(manufactured by Uniroyal Chemical Company), and the like, as well asmixtures thereof.

In embodiments, the optional antioxidant may be added to the adhesive,for example, in the amount of from about 0.1% to about 2%.

Examples of the optional filler suitable for use herein include titaniumdioxide, calcium carbonates, zinc oxide, clays, talcs and bariumsulfate.

In embodiments, the optional filler may be added to the adhesive, forexample, in the amount of from about 0.1% to about 5%.

In embodiments, the hot melt adhesive or pressure sensitive adhesive maybe applied to a substrate, and the adhesion promoter may be present atthe interface between the substrate and the adhesive. The adhesive maybe used to bind such articles.

In embodiments, the substrate may be a Xerographic print, includingXerographic prints contaminated with fuser oil, such as silicone oil.The substrate may include cast coat paper, gloss or silk coated paper,matte or plain paper, synthetic paper and offset pre-print forms. Othersuitable articles that may be bound include, for example, books andlaminating cards.

Embodiments described above will now be further illustrated by way ofthe following examples.

EXAMPLES Examples 1-3 Preparation of Buffer Solutions

Buffer Solution 1: Potassium phosphate dibasic (K₂HPO₄) powder (10grams) was dissolved in 90 g of distilled water at room temperature.

Buffer Solution 2: Sodium hydrogen sulfite (NaHSO₃) powder (10 grams)was dissolved in 90 g of distilled water at room temperature.

Buffer Solution 3: Potassium phosphate monobasic (KH₂PO₄) powder (10grams) was dissolved in 90 g of distilled water at room temperature.

Examples 4-6 Preparation of Silane Compositions

Silane Promoter 1: Into 50 grams of Silane A-2120[N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane from GE silicones]was added slowly 8 grams of Buffer Solution 1 with proper agitation atroom temperature. The resulting silane composition was kept stirring for3 hours before use.

Silane Promoter 2: Into 50 grams of Silane A-2120[N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane from GE silicones]was added slowly 8 grams of Buffer Solution 2 with proper agitation atroom temperature. The resulting silane composition was kept stirring for3 hours before use.

Silane Promoter 3: Into 50 grams of Silane A-2120[N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane from GE silicones]was added slowly 8 grams of Buffer Solution 3 with proper agitation atroom temperature. The resulting silane composition was kept stirring for3 hours before use.

Examples 7-9 Preparation of Hot Melt Adhesives

Adhesive 1: 100 g of HM220 (a hot melt adhesive available from HORIZON)was heated to 180° C. in a paint can with a heating mantle. Into themelt adhesive, 5 grams of plasticizer KAYDOL white mineral oil (fromCrompton Corp.) was added with an agitation speed of 250 rpm, followedby slow addition of 2.5 grams of the Silane Promoter 1 over about 10minutes. The resulting adhesive was stirred at 180° C. for another 30minutes before it was discharged.

Adhesive 2: 100 g of HM220 (a hot melt adhesive available from HORIZON)was heated to 180° C. in a paint can with a heating mantle. Into themelt adhesive, 5 grams of plasticizer KAYDOL white mineral oil (fromCrompton Corp.) was added with an agitation speed of 250 rpm, followedby slow addition of 2.5 grams of the Silane Promoter 2 over about 10minutes. The resulting adhesive was stirred at 180° C. for another 30minutes before it was discharged.

Adhesive 3: 100 g of HM220 (a hot melt adhesive available from HORIZON)was heated to 180° C. in a paint can with a heating mantle. Into themelt adhesive, 5 grams of plasticizer KAYDOL white mineral oil (fromCrompton Corp.) was added with an agitation speed of 250 rpm, followedby slow addition of 2.5 grams of the Silane Promoter 3 over about 10minutes. The resulting adhesive was stirred at 180° C. for another 30minutes before it was discharged.

Comparison Example 1

A control hot melt adhesive was prepared as follow: 100 g of HM220 (ahot melt adhesive available from HORIZON) was heated to 180° C. in apaint can with a heating mantle. Into the melt adhesive, 2.5 grams ofSilane A-2120 was added over about 10 minutes with an agitation speed of250 rpm. The resulting adhesive was stirred at 180° C. for another 30minutes before it was discharged.

Testing of Adhesive

Viscosity: The viscosity of the hot melt adhesives was measured byAR2000 Rheometer in a temperature range of 180° C. to 120° C. at a shearrate of 100 (l/s).

Thermal Stability: The adhesive thermal stability was evaluated asfollows: an adhesive sample was kept in oven at 180° C., and itsviscosity was monitored over 1˜8 hours.

The properties of the adhesives are summarized in Table 1.

TABLE 1 The Thermal Stability of Adhesives with adhesion promoter AgingTime (hrs) Viscosity (cp) @180° C. (180° C. in Oven) Control Adhesive 1Adhesive 2 Adhesive 3 0 4525 5222 5123 5238 2 6794 4943 5170 4988 8 81055223 5632 5396 Δη from 0 to 8 hrs 3580 1 509 158 Δη equals the change inviscosity over the indicated aging time.

By adding pure silane A-2120 without admixed with buffer solution, theviscosity increased more than 3500 cp after the adhesive was kept in anoven at an application temperature of 180° C. for 8 hours.

After Silane A-2120 was admixed with buffer solutions, the viscosityvariation can be controlled within 500 cp after the adhesive was kept inan oven at an application temperature of 180° C. for 8 hours. Thethermal stability of the adhesives is improved by admixing the silanewith a buffer solution.

Gluability

Test Procedure: The gluability was tested by using a homemade testerthat simulates a commercial hot melt adhesive binding application. Thefuser oil contaminated sheets used for the gluability test weregenerated by passing a paper (letter size 8.5″×11″) through a fusingfixture using typical silicone fuser oil. The paper typically containsfrom about 10 to about 60 micrograms of fuser oil. Onto the oilcontaminated paper was applied a hot melt adhesive, and laminated with asecond piece of paper to form a bound article. Paper tear (themeasurement of gluability) is measured by manually separating thearticle, and visually inspecting the area of the fiber tear: 0% meansthat there is no paper fiber tear, indicating poor binding adhesion, and100% means good and complete adhesion.

Test Results

Comparison Example 2

Gluability test results on Xerographic prints printed on coated anduncoated papers.

TABLE 2 Gluability comparison between commercially available hot meltadhesives and admixed silane promoted hot melt adhesive 3. XerographicPrints Paper Fiber Tear (%) Contaminated HM220 by Xerox Fuser CommercialUS661 Fluid 8R13030 Glue Commercial Glue Adhesive 3 10 pt KromeKote-F/F20 40 100 10 pt KromeKote-B/B 17.5 47.5 100 10 pt CornWall-F/F 0 0 10010 pt CornWall-B/B 50 85 99 Color Xpressions+ 5 17.5 97.5 10 pt EliteDigital Color 25 50 95 Gloss Cover 110 lb Luna Matte 0 20 95 80 lbDigital Color Elite 0 5 82.5 Gloss Text 80 lb Digital Color Elite 0 5 80Silk Text 110 lb Digital Color Elite 0 27.5 100 Gloss Cover

Comparison Example 3

Gluability test results on Xerographic prints printed on offsetpre-print forms.

TABLE 3 Gluability comparison between commercially available hot meltadhesive and admixed silane promoted hot melt adhesives 1–3. XerographicPaper Fiber Tear (%) Prints Contaminated HM220 by Xerox Fuser CommercialFluid 8R12936 Glue Ahesive 1 Ahesive 2 Ahesive 3 RSG Offset Pre-Print 077.5 55 72.5 Form

TABLE 4 Gluability comparison between commercially available hot meltadhesive and admixed silane promoted hot melt adhesive 3. Paper FiberTear (%) Xerographic Prints Contaminated HM220 by Xerox Fuser Fluid8R12936 Commercial Glue Adhesive 3 Vanguard_Green 0 100 Foundation_LightGreen 0 85 Seagate_Light Gray 0 100 Vanguard_Dark Grey 0 95 QVC_Green 092.5

By adding a small amount of the admixed silicone compound A-2120 to acommercially available adhesive such as HM220, the fiber tear increasesfrom 0 to about 100% on Xerographic prints printed on offset pressespre-print forms.

The gluability test results showed that the adhesives with admixedsilane compound as an adhesion promoter can bind Xerographic prints,which are generated using high content functional group fuser oil.

Example 10 Surface Free Energy Measurements on Substrates

The surface free energy SFE of the Xerographic prints generated onfusing fixture was lowered dramatically by contaminated substrates ormedia or by increasing the content of functional group in fuser oil.

Procedures on Contact Angle Measurement

Contact angles are measured by Fibro DAT1100 at temperature 23° C. andRH 50%. Before the measurement, the substrates or media was conditionedin room with 23° C. and RE 50% for more than 8 hrs. Three solvents areused for the CA measurement, Water, Formamide, Diiodomethane.

Surface Free Energy Test Results

Surface Free Energy is calculated by L W (Lewis) Acid/Base Method.

TABLE 5 Surface Free Energy comparison on No Oil, Xerox Fuser Fluid8R12936, Xerox Fuser Fluid 8R13030 fuser oil Contaminated Offsetpreprint forms Xerox Fuser Fluid Xerox Fuser Fluid Paper Description NoOil 8R12936 8R13030 Vanguard (RSG)_Green 42.82 15.33 12.55 Vanguard-DarkGreen 44.33 14.24 11.93 Gateway-Light Green 31.46 28.55 15.61Seagate-Light Green 40.47 12.49 10.99 Fundation-Light Green 43 18.5411.62 QVC-Green Side 42.61 13.28 11.37

TABLE 6 Surface Free Energy comparison on Xerox Fuser Fluid 8R12936,Xerox Fuser Fluid 8R13030 fuser oil contaminated cast coat papers andgloss and silk coated papers Xerox Fuser Fluid Xerox Fuser Fluid PaperDescription 8R12936 8R13030 10 pt KK_Coated Side 30.71 21.84 10 ptKK_Uncoated Side 24.51 20.66 10 pt CW_Coated Side 27.20 23.06 10 ptCW_Uncoated Side 40.47 8.92 10 pt Elite Digital Color Gloss 26.14 18.33Color Xpressions+ 17.71 12.99 110 lb Luna Matte 45.43 25.64

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Also,various presently unforeseen or unanticipated alternatives,modifications, variations or improvements therein may be subsequentlymade by those skilled in the art, and are also intended to beencompassed by the following claims. Unless specifically recited in theclaim, steps or components of claims should not be implied or importedform the specification or any other claims as to any particular order,number, position, size, shape, angel, color, or material.

1. A hot melt adhesive or pressure sensitive adhesive including at leastone adhesive material and at least one adhesion promoter comprising asilane composition formed by admixing a hydrolytic silane compound withan aqueous buffer solution.
 2. The adhesive according to claim 1,wherein the silane composition has a concentration ranging from about0.1% to about 5% weight percent of the total adhesive.
 3. The adhesiveaccording to claim 1, wherein the adhesion promoter is a hydrolyticsilane compound comprising at least one silane group of—Si(R)_(3-m)X_(m), wherein R is an non-hydrolyzable organic group, X isa hydrolytic group and m is an integer of 1 to
 3. 4. The adhesiveaccording to claim 3, wherein X is selected from the group consisting ofhalide, a hydroxyl group, a carboxylate group, an alkoxy group, anarylalkyloxy group, and an aryloxy group.
 5. The adhesive according toclaim 3, wherein the promoter is hydrolytic silane compound contains intotal two of the hydrolytic X group.
 6. The adhesive according to claim1, wherein the hydrolytic silane compound further comprises a functionalgroup selected from the group consisting of an amino group, a mercaptogroup, an epoxy group, and a vinyl group.
 7. The adhesive according toclaim 1, wherein the hydrolytic silane compound is selected from thegroup consisting of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane,N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,N-(2-aminoethyl)-3-aminopropylethyldiethoxysilane,N-(2-aminoethyl)-3-aminopropyltriethoxysilane4-Aminobutyltriethoxysilane, 1-Amino-2-(Dimethylethoxysilyl)propane,N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane,N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane,(aminoethylaminomethyl)phenethyltrimethoxysilane,N-(2-aminoethyl)-3-aminopropylsilanetriol,N-(6-aminohexyl)aminomethyl-trimethoxysilane,N-(6-aminohexyl)aminopropyl-trimethoxysilane,N-(2-aminoethyl)-11-aminoundecyl-trimethoxysilane,3-aminopropylmethylbis(trimethylsiloxy)silane,3-aminopropyldimethylethoxysilane, 3-aminopropyltrimethoxysilane,3-aminopropyltris(methoxyethoxyethoxy)silane,(3-trimethoxysilylpropyl)diethylene-triamine,3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,aminoethylaminopropyltrimethoxysilane,aminoethylaminopropyltriethoxysilane, or mixtures thereof.
 8. Theadhesive according to claim 1, wherein the aqueous buffer solutionpossesses a pH value ranging from about 2 to about
 10. 9. The adhesiveaccording to claim 1, wherein the aqueous buffer solution contains abuffer agent, wherein the buffer agent is an alkali metal phosphate oran alkali metal sulfite selected from the group consisting of potassiumphosphate dibasic, potassium phosphate monobasic, sodium hydrogensulfite, and mixtures thereof.
 10. The adhesive according to claim 9,wherein the ratio of the silane to the water in the buffer solution iswithin the range from 1:0.05 to 1:0.5 by weight, and wherein the ratioof the silane to the buffer agent in buffer solution is within the rangefrom 1:0.005 to 1:0.25 by weight.
 11. The adhesive according to claim 1,wherein the at least one adhesive material comprises at least onepolymer resin and a tackifier.
 12. The adhesive according to claim 11,wherein the polymer resin is selected from the group consisting ofpolyethylene, poly(ethylene/vinyl acetate), polystyrene,phenol-formaldehyde resin of polymer or block copolymer, polypropylene,styrenic block copolymers (SIS, SBS, SEBS), polyacrylate, polyvinylalcohol, polyalkylene oxide, polyamides and polyesters, APAO,polyurethane prepolymers and thermalplastic acrylic polymers, naturalrubber, and copolymers thereof, and wherein the tackifier is selectedfrom the group consisting of natural rosin, modified rosin, hydrocarbonsand hydrogenated hydrocarbons, mixed C5/C9 resins, pure monomers orhydrogenated pure monomers.
 13. An adhesive according to claim 11,wherein the at least one adhesive material further comprises a wax, aplasticizer, an antioxidant and/or a filler.
 14. An adhesive accordingto claim 13, wherein the wax is selected from the group consisting ofpolypropylenes, polyethylenes, natural waxes, paraffin wax, andsemicrystalline flexible polyolefins with a melting point from about 50°C. to about 150° C., wherein the plasticizer is comprised of whitemineral oil or polyisobutylene, wherein the antioxidant is comprised ofprimary and secondary antioxidant or multifunctional antioxidant, orhydroxylamines, and wherein the filler is comprised of titanium dioxide,calcium carbonates, zinc oxide, clays, talcs or barium sulfate.
 15. Abound article comprising at least a substrate, a hot melt adhesive or apressure sensitive adhesive applied on a substrate, and an adhesionpromoter present at the interface between the substrate and theadhesive, wherein the promoter comprises a silane composition formed byadmixing a hydrolytic silane compound with an aqueous buffer solution.16. A bound article according to claim 15, wherein the substrate isselected from a Xerographic print and a Xerograhpic print contaminatedwith silicone oil.
 17. A bound article according to claim 15, whereinthe substrate is selected from the group consisting of cast coat paper,gloss or silk coated paper, matte or plain paper, synthetic paper, andoffset pre-print forms.
 18. A bound article according to claim 16,wherein the substrate has a surface with a surface free energy rangingfrom about 8 mN/nm² to about 30 mN/m².
 19. A bound article according toclaim 15, wherein the hydrolytic silane compound comprises at least onesilane group of —Si(R)_(3-m)X_(m), wherein R is an non-hydrolyzableorganic group, X is a hydrolytic group and m is an integer of 1 to 3.20. A bound article according to claim 15, wherein the hydrolytic silanecompound contains in total two of the hydrolytic X group.
 21. A boundarticle according to claim 15, wherein the hydrolytic silane compoundfurther contains a functional group selected from the group consistingof an amino group, a mercapto group, an epoxy group and a vinyl group.22. A bound article according to claim 15, wherein the hydrolytic silanecompound is selected from the group consisting of an aminoalkylsilane, amercaptoalkylsilane or mixtures thereof.
 23. A bound article accordingto claim 15, wherein the hydrolytic silane compound isN-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane,N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,N-(2-aminoethyl)-3-aminopropylethyldiethoxysilane,N-(2-aminoethyl)-3-aminopropyltriethoxysilane4-Aminobutyltriethoxysilane, 1-Amino-2-(Dimethylethoxysilyl)propane,N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane,N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane,(aminoethylaminomethyl)phenethyltrimethoxysilane,N-(2-aminoethyl)-3-aminopropylsilanetriol,N-(6-aminohexyl)aminomethyl-trimethoxysilane,N-(6-aminohexyl)aminopropyl-trimethoxysilane,N-(2-aminoethyl)-11-aminoundecyl-trimethoxysilane,3-aminopropylmethylbis(trimethylsiloxy)silane,3-aminopropyldimethylethoxysilane, 3-aminopropyltrimethoxysilane,3-aminopropyltris(methoxyethoxyethoxy)silane,(3-trimethoxysilylpropyl)diethylene-triamine,3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,aminoethylaminopropyltrimethoxysilane,aminoethylaminopropyltriethoxysilane, or mixtures thereof.
 24. A boundarticle according to claim 15, wherein the aqueous buffer solutioncontains a buffer agent and possesses a pH value ranging from about 2 toabout 10, and wherein the buffer agent is an alkali metal phosphate oran alkali metal sulfite.
 25. A bound article according to claim 24,wherein the buffer agent is selected from the group consisting ofpotassium phosphate dibasic, potassium phosphate monobasic and sodiumhydrogen sulfite, and mixtures thereof.
 26. A bound article according toclaim 24, wherein the ratio of the silane to the water in buffersolution is from about 1:0.05 to about 1:0.5 by weight and wherein theratio of the silane to buffer agent in buffer solution is from about1:0.005 to about 1:0.25 by weight.
 27. A bound article according toclaim 15, wherein the adhesive promoter is pre-applied on the substrate.28. A bound article according to claim 15, wherein the promoter isincluded in the adhesive at a concentration ranging from 0.1% to 5% byweight percent of the total adhesive.
 29. A bound article according toclaim 15, wherein the article is a book or laminating card.
 30. Aprocess of binding a hot melt adhesive to a Xerographic print,comprising applying a silane compound treated with at least one bufferagent to a hot melt adhesive and applying the hot melt adhesive to theprint having a surface energy of about less than about 30 mN/m².
 31. Theprocess according to claim 30, wherein the surface energy of about lessthan about 30 mN/m² is due to fuser oil on the surface of the print. 32.The process according to claim 30, wherein an aminosiloxane oil ispresent on the Xerographic prints.